1, the representation of the set:

A set is represented by curly braces {}, and the elements in the set are separated by commas.

For example, {1, 2, 3, 4} represents a set with four elements.

2. Operation of sets:

Union: the union of two sets is represented by the symbol union, that is, all elements in the two sets are merged into a new set.

Intersection: use symbolic intersection to represent the intersection of two sets, that is, the * * * in the two sets and the elements they have form a new set.

Difference set: Symbolic difference is used to represent the difference set between one set and another set, that is, the elements in this set that do not belong to another set form a new set.

3. Relationship setting:

Relationship between elements and collections:

Element belongs to set: it is indicated by the symbol ∑, such as A∑{ 1, 2,3}, which means that element A belongs to set {1, 2,3}.

Element does not belong to a collection: Use symbols? Say, like one? {1, 2,3}, which means that element A does not belong to the set {1, 2,3}.

4. Settings of power pack:

Power set refers to all possible subsets of a set, which are represented by symbolic power sets. For example, the power set of the set {1, 2} is 1, 2, 1, 2,

5. Cardinality of the set:

The cardinality of a set represents the number of elements in the set, which is represented by a symbol card. For example, card({ 1, 2,3}) = 3, which means that the set {1, 2,3} has three elements.

Set is a basic concept in mathematics, which is a whole composed of some definite elements. Set theory is a subject that studies sets and their operations. In mathematics, we often use capital letters to represent sets, such as A, B, C, etc. A collection can contain any type of elements, such as numbers, letters, graphics, etc. We can classify elements with the same characteristics into one category and form a set. For example, all positive integers form a set, and all circles form a set.